Patent GB-1346301-A (GB)
Title: Methods for mixing and or dispensing liquids and apparatus therefor
IPC: B05B17/06
Filed: 1970-03-13
Abstract: 1346301 Mixing; chromatography; analysis using charged droplet stream; drop forming nozzles ADLER AUTO PRECISION Ltd 19 April 1971 [13 March 1970 19 June 1970 22 Aug 1970 18 Sept 1970 (2)] 12202/70 29886/70 40554/70 44545/70 and 44546/70 Headings B1C B1X and B2F [Also in Division G1] A method of mixing a liquid with at least one different liquid comprises passing one of the liquids through a drop generator to provide a stream of uniformly sized droplets, electrostatically charging at least some of the droplets, and contacting at least one charged or uncharged droplet from the stream with the other liquid or liquids. The droplets may be generated by a device comprising a capillary tube vibrated by a piezoelectric transducer. The droplets may be charged by passage through a hollow cylindrical charging electrode. The path of the charged droplets may be regulated by deflecting plates across which a potential difference is applied. The droplets may alternatively be generated by means of an electromagnetically driven diaphragm or a fluidic device in which a stream of liquid is segmented into droplets.  Dispensing. Liquids to be analysed may be dispensed in sequence through a drop generator of the kind described, at least some of the droplets may be electrostatically charged, and a selected number of charged or uncharged droplets uncontaminated with any previously passed liquid may be directed in a direction to permit analysis thereof, and contaminated droplets and uncontaminated droplets in excess of the selected number may be directed to waste.  Analysis. A sample of a liquid to be analysed may be reacted with a reagent using: the method of mixing described. For example, the cholesterol content of blood serum may be determined by bombarding a drop of reagent (Lieberman-Burchard) with droplets of blood serum to form a coloured reaction compound, and measuring light absorption properties of the latter in order to determine the cholesterol content, (Fig. 1 not shown). The analysis of other components of blood serum e.g. albumin, alkaline phosphatase, and blood urea nitrogen may be carried out using a single drop generator for the blood serum, and a multiple detection system. The reagent drop may be suspended from a tip, or enclosed in a container with inlet and outlet holes. Alternatively, both the blood serum and reagents for determining components thereof may each be passed through drop generators, each reaction being carried out in a separate vessel mounted on a rotatable holder and being monitored by means of a single spectrophotometric system employing a rotatable optical filter wheel, (Figs. 3-5, not shown). According to another embodiment, different components of blood serum are separately analysed using apparatus which provides for the supply of more than one reagent for the determination of each component, (Figs. 6-9 not shown). The method of mixing can be used for titrimetric analysis, in which case a pH meter may be used to determine the end point.  Chromatography. The method of mixing may be used to prepare solvent gradients for use in liquid chromatography, (Fig. 10 not shown). The analytical apparatus utilising the method of mixing may be controlled to perform automatically a pre-determined cycle of operations. For example, any desired solvent gradient may be obtained using a digital tape programme or a programmed timing wheel.